Depends on a lot of variables. It's not just the ice, but wind loading upon
the steel + ice + coax + rotor + whatever other forces are acting on the
tower. And of course, did the installation meet mfgr specs (how are they
rated for wind/ice loading), what's the soil like, are the tower footings
intact, etc., etc. The answers to these questions are often educated
guesses.
About 7-8 years ago we had an amazing ice storm, I had over 1/2" radial ice
on everything, and the storm hit before I could lower the tower (TriEx
LM470). Once the ice was on we then got 30-40 MPH winds. It survived (so did
the antennas!), but I was biting my nails the whole time. It took 3 days
before the sun came out, and slowly it all melted and amazingly the antenna
spring back to original shape.
Since that nail-biter, I always try to play cautious and lower "my
investment" when inclement weather is forecast.
Last night, as the storm approached I went to lower the tower...there was
already a thin layer of ice on everything. Started the motor and the fuse
blew (usually indicates too big a mechanical load or water intrusion in the
motor relay or starter caps). This summer I did major preventative
maintenance, including replacing the motor caps/relay so I didn't think it
was them. Replaced the fuse and motored the tower UP a little. Fuse didn't
blow this time and then I was able to break a little of the ice free, then
motor DOWN about 3-4 feet, then motor UP, then DOWN, etc. This eventually
broke all the ice free (much of it fell on me) and I was able to get the
whole structure down. Usually a full retraction takes about 6 minutes, last
night it took 20 minutes what with all the UP/DOWN. It's amazing how strong
a thin layer of ice is on all the cables and steel surfaces!
I was lucky...so were you!!!
Looking out the window now it looks like Siberia. I don't expect to do much
operating the next few days!
73
Dan
K0DAN
----- Original Message -----
From: "Dan Bookwalter" <n8dcj@yahoo.com>
To: <TowerTalk@contesting.com>
Sent: Tuesday, February 01, 2011 7:45 AM
Subject: [TowerTalk] TX-472 and Ice
>I went out this morning to crank the tower down for the pending Ice storm ,
>the
> problem is that the top section is stuck , i got lucky i was cranking away
> and
> looked up and saw about 10-12 feet of cable hanging out the side of the
> tower ,
> which scared me to death , i quickly cranked it back up before the top
> section
> broke loose , my question is with nothing on top of the tower except a
> wire
> antenna , will the tower handle up to a 1/2 inch of ice when it is
> extended to
> about 60-65 feet ? i don't think we are supposed to get any major wind
> just
> sleet and ice.
>
> thoughts.....
>
> Dan N8DCJ
>
>
>
>
> _______________________________________________
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